Increase of sensitivity at autoradiography by the latensification technique

Increase of photographic sensitivity by the latent image intensification (latensification) technique was studied at β-radiation autoradiography. Well-known post-exposure latensification, gold latensification, gold hypersensitization and prolonged development treatments were used, and new simultaneous red-light exposure treatment was also examined according to the latent image formation theory. Each single treatment increased the sensitivity a little. Combination of the treatments, especially with the prolonged development was effective. Large increase of sensitivity was obtained with a combination of the simultaneous red-light exposure and the prolonged development, although some fog appeared. The dispersion of latent image specks was intense at the β-radiation, and so many small and undevelopable silver specks were formed. They could not get the developability with the single treatment, but could do with the combination. The simultaneous red-light exposure would reorganize those specks to large and developable specks. (author)